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hint只是在原有的视音频轨道上增加一些流化信息，因此它和是否能够快进快退没有关系，只和文件能否流化有关系。换句话说，没有hint过的mp4文件也是可以快进快退的。
hint的具体解释可以参考下面这段英文： Hint tracks are a series of instructions in a mp4 container file that tell a server how to transmit packets. Hint tracks always refer to another track, most likely an audio or video media track. This series of instructions tells the server when to send the packet, what type of RTP header to add, if there is any extra data in the packet, and how much data to send in the packet. To save on space, a hint can contain a pointer to the media track, instead of duplicating that data. It will also tell what SDP to add for the track that is referenced. So, a file that is hinted should have a media track, and an associated hint track for that media track. There are some mp4 container files that just have hint tracks - these are called "fat hints " and are usually not playable locally. These are illegal in ISMA, so we won 't talk about them. To create hint tracks for a mp4 file is fairly simple with the mp4creator program. Just execute the: mp4creator -hint= <track to hint track number> [-p <payload> ] <mp4file> For example: [wmay@wmaytclinux2 content]$ mp4info xvid.mp4 mp4info version 0.9.5.4 xvid.mp4: Track Type Info 1 video MPEG-4 Simple @ L3, 3.695 secs, 627 kbps, 608x256 @ 23.00 fps 2 od Object Descriptors 3 scene BIFS I would execute the: mp4creator -hint=1 xvid.mp4 and get: [wmay@wmaytclinux2 content]$ mp4info xvid.mp4 mp4info version 0.9.5.4 xvid.mp4: Track Type Info 1 video MPEG-4 Simple @ L3, 3.695 secs, 627 kbps, 608x256 @ 23.00 fps 2 od Object Descriptors 3 scene BIFS 4 hint Payload MP4V-ES for track 1 -----------------------------------------------------------------------------------
机顶盒播放的是流媒体，streaming
同时机顶盒接收到的可能是RTP包或者其他协议的包 Hint可以按照RTP等协议对原来的MP4文件进行index，方便RTP的发送 所以没有Hint就没有办法发送流媒体，机顶盒就没有办法接收并播放，同样更没有办法快进了 不知道你说的是什么机顶盒？ |
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